Bio-mediated Geo-material Strengthening for engineering applications

Project Information

BIOGEOS

Grant agreement ID: 788587

DOI

10.3030/788587

Project closed

EC signature date 19 April 2018

Start date 1 November 2018

End date 30 April 2024

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 497 115,00

EU contribution

€ 2 497 115,00

Coordinated by

ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE
Switzerland

Periodic Reporting for period 4 - BIOGEOS (Bio-mediated Geo-material Strengthening for engineering applications)

Reporting period: 2023-05-01 to 2024-04-30

Summary of the context and overall objectives of the project

BIOGEOS focuses on developing and characterizing biocementation processes for civil engineering applications, aiming to provide sustainable alternatives to traditional cement-based methods. Traditional practices often involve the use of environmentally impactful artificial cement or petroleum derivatives. In contrast, biocementation leverages nature-inspired processes, particularly microbial-induced calcium carbonate precipitation (MICP), to strengthen geo-materials. Understanding biocementation requires investigation into contributing mechanisms such as microbial metabolic activities, flow and transport phenomena, and chemical reactions. This entails studying the microscale processes, including the internal architecture of biocemented materials, to ultimately characterize the formation of biocementation and determine the resistance properties. BIOGEOS employs a multidisciplinary approach across three key facets: microscale investigations, geotechnical lab-scale studies, and numerical simulations. Experimental tools encompass high-resolution microscopy techniques, microchip porous devices, and computed microtomography, while theoretical frameworks include algorithms for flow characterization and image processing techniques. A summary of the advancements in the project includes, but is not limited to: (i) precise control over the amount and location of calcium carbonate at the scale of real geotechnical works; (ii) treatment of the residual nitrogen waste in an effort to establish fully circular biocementation applications; (iii) new application approaches, including treatment protocols via encapsulated biocementation agents or protocols for treating clays, which were considered previously as materials out of the range of potential improvement using biocementation.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Specifically, the project's accomplishments encompass a wide range of facets and scales, extending from microscale observations of reactive transport flows to laboratory testing, advanced image processing utilizing sophisticated algorithms, and large-scale pilot applications. More precisely a selection of the achievements and relevant output are summarized below:


a) Microscale studies involve real-time observation of biocementation initiation and evolution using video microscopy on microfluidic devices, coupled with image processing algorithms.

Relevant publication: Elmaloglou, A., Terzis, D., De Anna, P. and Laloui, L., 2022. Microfluidic study in a meter-long reactive path reveals how the medium’s structural heterogeneity shapes MICP-induced biocementation. Scientific Reports, 12(1), p.19553.
https://www.nature.com/articles/s41598-022-24124-6

b) Application and quality assessment/control of biocementation at the scale of real geotechnical works, including novel approaches like ex-situ hydrolysis to eventually treat residual ammonium which commonly represents a bottleneck in traditional biocementation applications.

Relevant publication: Harran, R., Terzis, D. and Laloui, L., 2023. Addressing the challenges of homogeneity, quality control and waste handling in soil bio-cementation: a large-scale experiment. Soils and Foundations, 63(4), p.101332.
https://www.sciencedirect.com/science/article/pii/S0038080623000616

c) Characterization of the porous matrix using advanced computed microtomography tools.

Relevant publication: Roy, N., Frost, J.D. and Terzis, D., 2023. 3-D contact and pore network analysis of MICP cemented sands. Granular Matter, 25(4), p.62.
https://link.springer.com/article/10.1007/s10035-023-01347-6

d) The establishment of a bio-chemo-hydro-mechanical model of transport, strength and deformation for bio-cementation applications which can easily be calibrated with existing experimental results. The model application is demonstrated through the case of a 2D shallow foundation strengthening via biocementation.

Relevant publication: Bosch, J.A. Terzis, D. and Laloui, L., 2024. A bio-chemo-hydro-mechanical model of transport, strength and deformation for bio-cementation applications. Acta Geotechnica, pp.1-17.
https://link.springer.com/article/10.1007/s11440-023-02172-0

e) Investigations into the influence of applied direct currents on biocementation processes, including extensive crystalline characterization analysis.

Relevant publication: Terzis, D., Hicher, P. and Laloui, L., 2020. Direct currents stimulate carbonate mineralization for soil improvement under various chemical conditions. Scientific Reports, 10(1), p.17014.
https://www.nature.com/articles/s41598-020-73926-z

f) Development of a novel system for producing biocementation agents in the form of microcapsules activated under controlled environments.

Relevant publication: Saracho, A.C. Lucherini, L., Hirsch, M., Peter, H.M. Terzis, D., Amstad, E. and Laloui, L., 2021. Controlling the calcium carbonate microstructure of engineered living building materials. Journal of Materials Chemistry A, 9(43), pp.24438-24451.
https://pubs.rsc.org/en/content/articlehtml/2021/ta/d1ta03990c

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The advancements achieved in the BIOGEOS project significantly contribute to the progression of the research field, paving the way for the integration of biocementation technology into real-world geotechnical practice. Through the production of state-of-the-art papers [1,2] capturing the evolution of the field within the project's domains of interest, BIOGEOS has established itself as a cornerstone in advancing biocementation research.

The project's adoption of a multiphysical and multiscale approach has played a key role in maturing the technology and propelling its future integration prospects. Main questions addressed during the project include the spatiotemporal evolution of biocementation, the influence of varying pore space properties on the precipitated matrix outcome, the application and monitoring of biocementation at large scales, mitigation strategies for residual ammonium waste, and the utilization of numerical tools to simulate future biocementation applications.

By providing answers to these critical questions and insights into previously unexplored physical mechanisms, the scientific output of the project has established a new foundation for the future of bio-geotechnical engineering. The knowledge gained from BIOGEOS sets the stage for further advancements in sustainable infrastructure development and environmental remediation through the innovative application of biocementation technology.

[1] Harran, R., Terzis, D. and Laloui, L., 2023. Mechanics, modeling, and upscaling of biocemented soils: a review of breakthroughs and challenges. International Journal of Geomechanics, 23(9), p.03123004.
[2] Terzis, D. and Laloui, L., 2019. A decade of progress and turning points in the understanding of bio-improved soils: A review. Geomechanics for Energy and the Environment, 19, p.100116.

Schematic section of the large-scale experimental setup and injection system.

XRD patterns of ten samples of MICP (no applied DC) and EA-MICP (applied 5 V of DC) samples

Results of the numerical simulations. The contour lines indicate the CaCO3 content

Schematic representation of the microfluidics experimental setup.

Example visualization of the image analysis steps (3D micro-tomography)

Effect of the hydrogel on the CaCO3 structure.